1. Field of the Invention
An aspect of the present invention relates to a ribbon for a photovoltaic module, through which solar battery cells are connected.
2. Description of the Related Art
Solar batteries function to convert solar energy to electrical energy. The solar batteries are manufactured using a semiconductor material such as silicon, gallium-arsenide, cadmium-telluride, cadmium-sulfide, indium-phosphorus or mixture thereof, and the silicon is mainly used as the semiconductor material.
A solar battery is manufactured by forming the p-n junction of a semiconductor material using a diffusion method, and uses the photovoltaic effect in which a small amount of current flows when the solar battery receives light. A solar battery is generally composed of a large-area p-n junction diode, and an electromagnetic force generated between both electrode terminals of the p-n junction diode is applied to an external circuit, thereby acting as a unit solar battery or solar battery cell.
Since the electromagnetic force generated from the solar battery cell is small, a plurality of solar battery cells is connected through a bus to form a photovoltaic module that generates a desired electromagnetic force.
FIG. 1 is a plan view of a conventional photovoltaic module.
In the conventional photovoltaic module, a plurality of solar battery cells 110 is arranged at an interval, and two interconnection ribbons 120 and 122 are connected to one solar battery cell 110. The interconnection ribbons of one solar battery cell 110 and the interconnection ribbons of another solar battery cell are connected to a bus ribbon 130. The bus ribbon 130 is connected to a load (not shown) that requires electric power.
Electric charges in the photovoltaic module flow in the two interconnection ribbons 120 and 122 and then move to the straight-line bus ribbon 130 connected perpendicularly to the interconnection ribbons 120 and 122.
In order to form the bus ribbon in a practical process, the bus ribbon 130 is cut to a predetermined length and then connected to string portions of the interconnection ribbons 120 and 122 through welding.
However, since such bus ribbon structure is connected to the interconnection ribbon as wide as the bus ribbon, and the connected portion is perpendicularly bent, resistance is changed depending on the position of the interconnection ribbon, and accordingly, serial resistance increases at the connected portion between the bus ribbon and the interconnection ribbon.
Because of small contact area between the interconnection ribbon and the bus ribbon, problems occur that contact resistance between the interconnection ribbon and the bus ribbon increases, and resistance increases too due to concentrated current at the perpendicularly bent portion.